As many as 73 Syrian military officers - including seven generals and 20 colonels - have crossed the border with their families "seeking refuge" in Turkey, the country's state-run news agency reported Friday.

The Anadolu Agency said the group - totaling 202 people - arrived in the border town of Reyhanli and were taken to a Turkish refugee camp that houses military officers who have defected from the Syrian army.

The report did not say when they had arrived and Turkish Foreign Ministry officials and the local administrator in Reyhanli could not immediately confirm the report.

Also on Friday, Russian Foreign Minister Sergei Lavrov told U.S. Secretary of State John Kerry that more U.S. military support for forces opposed to Syrian President Bashar Assad could stoke violence in the Middle East.

During a telephone conversation, Lavrov "stressed that such a step (military support) risks escalating (violence) in the region, while accusations against Damascus of the use of chemical weapons by the United States are not backed up by verified facts," the foreign ministry statement said.

The report of the defections come after U.S. President Barack Obama authorized lethal aid to Syrian rebels following a U.S. announcement that it had conclusive evidence that the Syrian regime used chemical weapons against opposition forces.

Syria's government used the nerve agent sarin on two occasions in the embattled city of Aleppo in March and April, according to a letter from a top U.S. diplomat that The Associated Press obtained Friday.

The letter from U.S. Ambassador Susan Rice to UN Secretary-General Ban Ki-moon also cited two other incidents of possible chemical weapons use by the regime of President Assad.

But Ban said Friday he opposes the U.S.decision to send weapons and that there can be no certainty of chemical weapons use in Syria without an on-the-ground investigation. The UN chief reiterated his longstanding position that there is no military solution to Syria's two-year-old conflict, which has killed more than 93,000 people. He said increasing the flow of weapons to either side "would not be helpful."

"The validity of any information on the alleged use of chemical weapons cannot be ensured without convincing evidence of the chain-of-custody," Ban said.

Rice, who will become Obama's national security adviser in July, told reporters Friday that the U.S. government is "very confident" in its assessment. "We've taken two months to reach this through a very careful and deliberative process," Rice said.

In the letter to Ban, Rice said the United States has determined that sarin was used in a March 19 attack on the Aleppo suburb of Khan al-Assal and in an April 13 attack on the neighborhood of Shaykh Maqsud. She said unspecified chemicals, possibly including chemical warfare agents, were used May 14 in an attack on Qasr Abu Samrah and in a May 23 attack on Adra.

"The United States requests that the UN fact-finding mission include these incidents in its ongoing investigation and report, as appropriate, on its findings," Rice said.

Earlier on Friday, Turkey said the U.S. announcement corroborates its own findings and urged the international community to take a decisive stance against the regime's "atrocity." Turkey has said preliminary tests on some injured Syrians indicated that chemical weapons had been used.

A Turkish Foreign Ministry statement called on the international community to unite against Syrian President Bashar Assad. It stated the regime's attacks must be halted and a "democratic transition process" must start in Syria.

Once a close ally of Syria, Turkey turned into one of the Assad regime's harshest critics after the uprising began two years ago. Turkey is now a key supporter of the Syrian rebels, offering shelter for many senior and lower-ranking defected Syrian soldiers.

Haaretz.com, the online edition of Haaretz Newspaper in Israel, and analysis from Israel and the Middle East. Haaretz.com provides extensive and in-depth coverage of Israel, the Jewish World and the Middle East, including defense, diplomacy, the Arab-Israeli conflict, the peace process, Israeli politics, Jerusalem affairs, international relations, Iran, Iraq, Syria, Lebanon, the Palestinian Authority, the West Bank and the Gaza Strip, the Israeli business world and Jewish life in Israel and the Diaspora.